Australian sailors were involved in a tense standoff with Iranian forces in the Persian Gulf three years before 15 British sailors and marines were captured in a similar incident, the defense department said Friday. The Australians were conducting a similar role of searching ships in the Persian Gulf as the British personnel were when they were taken prisoner by an Iranian gunboat in March and accused of straying into Iranian waters. The 15 were released after nearly two weeks. The four-hour confrontation occurred in December 2004 after Australian navy personnel boarded a cargo ship that had run aground near the Iran-Iraq maritime border, navy Commodore Steve Gilmore told reporters in the capital, Canberra. The Australians were preparing to leave the stricken vessel in two inflatable craft when an Iranian gunboat approached, and then the Australian commander ordered his sailors back to the cargo ship. Another four Iranian military boats armed with rocket-propelled grenade launchers arrived to reinforce the first gunboat during the next 45 minutes, Gilmore said. "Over a tense period of four hours, the boarding party was eventually successfully extracted by helicopter" and flown back to their guided missile frigate, Gilmore said. No shots were fired during the encounter.